2002 Volume 51 Issue 12 Pages 789-798
A liquid chromatography method with filament yarn as the stationary phase has been developed for studying the mechanism by which oily soils are removed from a fiber substrate with an aqueous surfactant micellar solution. We measured the retention volume of 1-phenylazo-2-naphthylamine (SY5) and l-phenylazo-2-naphthylphenol (SY14) as two kinds of oily soil model on either polyester or cellulosic filaments (the stationary phase) as a function of sodium dodecyl sulfate (SDS) concentration in the mobile phase. The oily soil elution volumes and capacity factors were affected with the micelle concentrations. The partition coefficients of the oily soils between SDS micelles and the fiber substrate, between the fiber substrate and water (non-micellar solution), and between SDS micelles and water (non-micellar solution) were determined with the chromatographic treatment involving micellar mobile phases. The standard free energy changes of the soils from the fiber substrate into the micelles (-ΔG°ms), from water onto the fiber substrate (-ΔG°sw), and from water into micelles (-ΔG°mw) were also calculated from the partition coefficient data. The -ΔG°sw values for SY5 and SY14 onto the polyester were larger than those onto the cellulosic filaments, whereas the -ΔG°ms values onto the cellulose larger than those onto the polyester filaments. Thus, it was shown thermodynamically that the oily soils re-deposit more readily on polyester than on cellulosic filaments. That is why it is more difficult to remove oily soils from polyester than from cellulosic filaments with SDS solutions.
